The growing of mushrooms is done under controlled conditions for a lengthy period of time. Various standard techniques are known. Some of these techniques are described in U.S. Pat. No. 6,018,906, all of the details of which are incorporated herein by reference thereto. As pointed out, two common techniques for mushroom cultivation are in the use of mushroom beds or shelves and in a tray system. Other methods of growing mushrooms have been the bag system, the ridge bed system and deep trough system. These systems, particularly the bed and the tray systems include two distinct phases. Phase I is generally done outdoors and involves composting the material to be used for cultivating the mushrooms. The compost is then conveyed into a mushroom house and fills the receptacles, such as beds or trays. In general, the compost is then heated to pasteurize the compost and ensure that the compost is free from most mushroom pests and diseases. The pasteurized compost then undergoes a cool down procedure. The pasteurizing step could take up to 14 days and the cool down procedure could take about 3 days. The next operation is the spawning where the compost is inoculated with mushroom mycelia by distributing particulate material colonized with mushroom mycelia (spawn) through the compost. The spawning run might take about 14 to 16 days. Next the colonized compost is covered by a layer of nutrient poor material or casing. The casing layer holds the moisture so that the mycelium must grow through the casing layer. The next step might be considered a flash step which occurs about twenty days after the mycelium breaks through the casing layer. The flash step is the first picking of cultivated mushrooms. Finally, after the mushroom heads break through the casing layer there is a final harvesting of the mushrooms. Reference is also had to U.S. Pat. Nos. 6,073,388 and 5,503,647, all of the details of which are incorporated herein with regard to mushroom growing techniques.
In order to provide the best form of cultivated mushrooms under these controlled conditions it would be desirable if there were some assurance of having the mushroom house in a sterilized condition to prevent outside contamination interfering with the mushroom growth. It has been known in other fields to use ozone as a means of sterilization. The use of ozone in connection with the growing of mushrooms, however, has not heretofore been contemplated. One reason, perhaps is that ozone might be considered to create detrimental aesthetic and health affects if the ozone contacts the mushrooms.